Fluid pump

Claim 1

A fluid pump for pumping gas at a well sit utilizing the well pumping unit as a prime mover comprising: a tubular cylinder defining an elongated chamber; piston means reciprocably disposed within said chamber; said piston means comprising: a. an elongated tubular piston rod having at the lower end thereof an upper transverse flange, said piston rod having the lower end thereof disposed within said cylinder and the upper end thereof articulatively interconnected to said prime mover; b. an inner elongated piston rod having at the lower end thereof a lower transverse flange; said inner piston rod being slidably received within said tubular piston and having the upper end thereof extending beyond the upper end of said tubular piston rod; c. a pliable non-metallic donut shaped piston ring interposed between said upper and lower flanges, and in sealing engagement with the inner wall of said chamber; and d. means interconnecting the upper ends of said piston rods and adapted to operably slide said inner piston rod relative to said tubular piston rod whereby said pliable piston ring is compressed radially outward to maintain said sealing engagement with the inner wall of said chamber; turnbuckle means articulatively attaching said cylinder to a stationary surface whereby adjustment of said turnbuckle varies the compression ratio of said apparatus; and external valving means interconnected to said housing for adjustably controlling the ingress and egress of fluid into and from said chamber whereby reciprocation of said piston means compresses said gas.